Protective toe cap for industrial footwear

ABSTRACT

The invention relates to a one-piece protective toe cap for safety footwear, forming a concave frame consisting of a front wall with connected side walls, the upper edges of which are joined by a concave surface along the profile of the last. The contour or edge of the flange of the toe cap is provided with a recess in order to house a tab and provide comfort, as well as improving the appearance of the footwear (not shown in these documents). The design withstands impact tests of approximately 101.7 to 146.7 Joules (10.4 to 14.95 kgf−m), leaving clearance of approximately 11 mm to 14 mm in the capped shoe and not only at the tip of the cap.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of previously filedco-pending Patent Applications, Application No. MX/a/2007/015351 andPCT/MX2008/000074.

FIELD OF THE INVENTION

The invention addresses the need to protect a worker who is performing aproductive activity in industry, a one-piece toe cap has been designedfor industrial protective footwear in which said toe cap is specificallydesigned to the protection of the five digits of the foot against impactand crushing by falling objects. The invention relates to a one-piecetoe cap for safety footwear that forms a concave 180° frame that housesan internal cavity supported by a horizontal interior flange that coversthe entire internal part of the perimeter of the toe cap 5 to 7 mm inwidth, the concave frame is composed of a front wall with side wallsconnected to both sides and whose upper edges are joined by a concavesurface following the profile of the last; the toe cap is previouslyprepared by the attachment in its mouth of a strip of synthetic materialknown as a tab and placed in the footwear through an insertion fitted tothe tip of the dressed last (a form that creates the footwear's size,fit and style), meaning by dressed last the prior attachment of anelement known as the sole to the bottom part of the last and anotherelement fitted three-dimensionally to the tip of the last known as thelining, the attachment of the toe cap being completed by a layer ofmaterial encircling the entire outer surface of the toe cap. The uppersurface has an edge on the side opposite the front wall having a recess.Furthermore, the invention relates to a method of calculating anddesigning a toe cap starting from a last.

BACKGROUND OF THE INVENTION

It is known that the Mexican company FOOTMEX DE MEXICO S. A. de C V.produces a commercial toe cap designed in two alternative materials,which are offered on the market as being economical and high-impact,basing its designs on two toe caps of commercial dimensions known asmodel 600 and 630.

Mexican utility model No. 796, granted on 13 Jul. 2000 to the companyCalzado Van Vien S .A. de C. V., relates to an armored tip forprotective footwear, formed by a section in the shape of a hollowsemiparabolic arch of high-strength steel sheet, intended to house andprotect the tip of the user's foot from forceful impacts, wherein thesection itself is folded at its lower end to form a horizontal flangethat spans the entire perimeter by the internal part of the tip, and theends of the inner horizontal flange have a bridge welded to the lowerface of the flange, whose purpose is to provide structural support tothe armored tip, to prevent its collapsing or flattening under theimpact of a force of significant magnitude.

Mexican patent number 225317, dated 4 Jan. 2005, granted to H. H. BROWNSHOE COMPANY, INC., describes a footwear and its method of manufacture.The footwear includes an upper that has a front lining with a tip partarranged along an internal surface of the upper. A relatively rigidfront insole part is joined to an inner lining, the length of the frontpart of the insole being less than the length of the inner lining. Thetip portion of the front lining is then sewn to a peripheral edge of thefront insole part, the front lining and the front insole part defining acavity to receive part of the user's foot. A steel tip is then placedbasically around the tip part of the front lining.

Spanish utility model No. 1062608 relates to an ergonomical shoe, of thekind incorporating between the leather and the lining, and in the areaof the toe and the heel, a rigid front reinforcement and a rear heelreinforcement, which participate both in the armoring of the leather andin the protection of the front foot from outside impacts, characterizedin that it incorporates shock absorbing elements in the area of thefront and rear reinforcements, adapted to the internal face of the frontand rear reinforcement and situated, the same as these, between theleather and the lining, said shock absorbing elements being made of asoft, high-density material, such as a foam of urethane, polyurethane,polyethylene, EVA, latex, silicone or another similar material withadequate density and breathability for the type of footwear.

Spanish utility model No. 1062609 relates to an ergonomical footwear, ofthe type having between its leather and its lining, and in the area ofthe tip or toe cap and the heel, a rigid front reinforcement and a rearreinforcement, which participate both in the armoring of the leather andin the protection of the front foot from outside impacts, characterizedin that each of these front and rear reinforcement elements has twolayers of different density, specifically, an outer layer of very highdensity, imparting hardness and rigidity to same, and an inner layer ofless density, which is softer and more comfortable and which is whatwill make contact with the foot via the lining of the footwear.

Spanish utility model No. 1065081 describes a reinforcement tip forsafety footwear that has an arched configuration that is designed formounting on the front part of a safety footwear used in certainindustries, characterized in that it is comprised of two parts or pieces(1) and (2), the first being rigid, of arched configuration, while thesecond part or piece (2) is of flexible material, and is joined byinjection molding to the rear part of the rigid piece (1), forming acontinuity with the latter.

Spanish utility model No. 2105370 describes a tip for a safety shoe orboot, to provide a tip which is light and has sufficient strength thetip is made of a compound material comprising a thermoplastic resin (7)reinforced with fiber and at least one wire mesh (4) that has a size of7 to 200 reticules and is included in the fiber-reinforced thermoplasticresin. In a preferred embodiment of said Spanish utility model, thefiber-reinforced thermoplastic resin comprises a thermoplastic layer (1)reinforced with long fiber and it has long reinforcement fibers (5)incorporated in it, and a thermoplastic layer (2) reinforced with shortfiber that has short reinforcement fibers (6) incorporated in it, andthe wire mesh (4) is included in the thermoplastic layer (2) reinforcedwith short fiber.

The differences lie in the fact that the aforementioned models describeaspects such as the assembly system, some materials of which arecomposites, and protective inserts in the tip of the foot; even so, theydo not define the design and development of a specific toe cap based onan anthropometric study and the parts of the foot to be protected,considering the ergonometric and functional aspects in variousactivities of the user, nor do they give a rule for evaluation of impactand compression results that they fulfill.

The aforementioned developments describe the use of a bridge that servesbasically to anchor the toe cap properly to the construction system;this bridge does not exist in the present invention. The dimensions arenot the same (width, height and internal depth). The dimensions of thetoe cap of the invention are adapted to the morphology of the worker'sfoot, and adequate construction materials have been included so as notto take up space from the toe cap which has the necessary space dictatedby the dimensions of the foot, considering the movements for the variousactivities of the user during the performance of his activity. The toecap of the invention has a recess in the contour or edge of the flange,designed to accommodate a tab and create comfort, as well as improve theappearance of the footwear, and the disclosure of these documents doesnot show this. The design of the invention withstands impact testing ofapproximately 101.7 to 146.7 Joules (10.40 to 14.95 kgf−m) andcompression of 11,130 to 14,710 Newtons (1135 to 1500 kgf−m), leaving afree height of approximately 11.0 mm to 14.0 mm, in the finished shoeand not only at the point of the toe cap.

The invention relates to a one-piece toe cap for safety and protectionfootwear, formed by a front wall with lateral walls connected to bothsides and whose upper edges are joined to a concave surface and in whichthe lower edges are provided with a flange providing it with rigidity,anchoring, stability and a base which further minimizes the movement ofthe toe cap and its sinking into the surface of the sole upon sustainingan impact or compression and at the same time serving to join the toecap to the sole.

In the case of the present invention, the safety footwear that is wornduring work has a toe cap to prevent injury to the front part of thefoot, by covering its five toes, from forces of sudden action, such asfalling objects. The prior art was researched, without result, for a toecap that provides coverage and protection to the five toes and that isstable, light, comfortable, and prevents injury to the five toes under amaximum impact, and is easy to manufacture. This need is only met by thetoe cap of the present invention, which is made from a single piece,whose material provides resistance to impact and is stable and light.Its design incorporates a broadened end part and an edge in the lowerzone, as termination of the front and lateral walls, at the same timeproviding rigidity to the terminal angle.

The toe cap is of a single piece, without any perforation for means ofattachment, with lateral walls and continuous sheet, with a spacearrangement sufficient to properly accommodate the five toes and at thesame time allow them to flex freely, providing a comfort not offered bythe toe caps on the market.

In the present invention, this toe cap is finished in keen edges forminga framework of original design, rigid and resistant to impact forces.

Another advantage is that, being made of a single piece, it facilitatesthe placement of the out covering material, which can be leather,synthetic, or textile, improving the final appearance of the footwear.

Another advantage is that the toe cap can be fabricated in a singlestep, and when produced on an industrial scale it provides majoreconomic, technical, protective and hygienic advantages.

Yet another advantage, and being different from the prior art, is thatit does not need grooves or bars connected in articulated fashion tosecure the toe cap to the bottom sheet, thus avoiding traction forceswhich result in deformation of the industrial footwear and reducedprotection for the foot, and becoming an unwanted risk element, to thecontrary of its purpose.

BRIEF SUMMARY OF THE INVENTION

The invention relates to a one-piece protective toe cap for safetyfootwear, forming a concave frame consisting of a front wall withconnected side walls, the upper edges of which are joined by a concavesurface along the profile of the last. The contour or edge of the flangeof the toe cap is provided with a recess in order to house a tab andprovide comfort, as well as improving the appearance of the footwear(not shown in these documents). The design withstands impact tests ofapproximately 101.7 to 146.7 Joules (10.4 to 14.95 kgf−m), leavingclearance of approximately 11 mm to 14 mm in the capped shoe and notonly at the tip of the cap. Therefore one objective of the invention isto start from a last obtained by anthropometric study of the workerwearing the safety and protective footwear, currently being filed for apatent by the same applicant of the present invention, and design,calculate and elaborate a one-piece toe cap to protect the five toes ofthe foot, defining heights, widths, depths and elements for balanceddistribution of impact forces.

A further object is to obtain a toe cap that complies at minimum withthe tests of the standard NRF-008-PEMEX-2001, impact strength of 101.7 J(10.4 kgf−m) and compression of 11,130 N (1135 kgf−m).

A further object is to develop a one-piece toe cap that effectivelyprotects the five toes with the maximum possible comfort, notinterfering with the free flexing and not promoting deformation of thefoot, being ergonomical in accordance with the morphology of the workerwearing the safety and protection footwear.

A further object is to develop a one-piece toe cap or effectiveprotector of the five toes for adequate use as individual protectiveequipment to reduce the economic and human costs occurring in thecountry from injuries to the feet of the workers wearing this product.

DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and objects of the invention,reference should be made to the accompanying drawings, in which:

FIG. 1A is a top view showing the line D-D′ which is the basis for thedesign of the toe cap and enables effective protection of the five toes.

FIG. 1B is a schematic top plan view of the foot indicating thedifferent measurements and parts of same involved in the design of thelast and toe cap of the present invention.

FIG. 2A is a top plan view showing the position of the toe cap withrespect to certain points used to determine the design and thedimensions of the toe cap.

FIG. 2B is a schematic lateral elevation view of the last on which thedifferent measurement lines and references are traced to design andcalculate the toe cap of the present invention.

FIG. 3 is a longitudinal sectional view of line D-D′ of FIG. 1A.

FIG. 4 is a view of the last of the preferred embodiment and itscorresponding plan view illustrating measurement points of the toe capof the present invention, in which one can see the location of the lowerline of line D-D′, and the line P-C which defines the width of the lastfor the design of the toe cap.

FIG. 5 is a front isometric view of the toe cap, showing its internalarch.

FIG. 6 is a lateral elevation view showing the height and general shapeof the toe cap.

FIG. 7 is a top plan view of the toe cap, showing the angles formed withregard to a straight line of the internal points of the width of the toecap between the internal and external point equivalent to around 5degrees as a result of the coverage for the 1st and 5th toes, therebygiving greater coverage to the 5th (little) toe.

FIG. 8 is a sectional view along the central longitudinal line of thetoe cap of FIG. 1A, showing a detail of the step for the tab of the toecap.

FIG. 9 is a view from the opposite side of the point of the toe cap.

FIG. 10 is an isometric view along line B-B′ of FIG. 9.

The foregoing v4ews show only the corresponding views of the right footfor simplicity of drawing and explanation of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The toe cap of the present invention has as one of its maincharacteristics the fact of protecting the five toes.

To cover and protect the five toes, one must take into account thefollowing points during the design and calculation:

1. Respect the line of flexure.

2. Consider the external length of the tab.

3. The anatomical distribution of the heads with the metatarsals.

4. The inclusion of the 5 toes.

5. The displacement of the foot while walking.

6. Thicknesses of the construction materials of the footwear.

Analysis of the zone of flexure of the toes, the position of themetatarsal heads and the foregoing considerations let one establish theanatomical aspects of the foot for the development of a protective toecap in a specific form that covers the five toes and at the same timeprovides a sufficient flexing zone so that the toe cap does not strikethe metatarsal heads of the foot.

It should be pointed out that the rim of the toe cap of the presentinvention has two angles (α, β), as shown in FIGS. 6 and 7; the toe capsof the prior art do not include these angles, which has the effect ofpreventing flexure of the foot while at least partly protecting the fivetoes.

To achieve the objectives of the invention, that is, to obtain aone-piece toe cap protective of the five toes for use in a protectivefootwear that effectively provides such protection, not causingdeformation, free of roughness, edges, points, being ergonomical and atthe same time letting the user perform his normal activity exposing himto risks with appropriate protection and of the required degree, thepresent toe cap is manufactured from materials not having harmfuleffects on the health.

The toe cap is of a single piece, nonmetallic, although in an alternatemodality it can also be manufactured from a metallic material.

As can be seen in FIG. 3, the toe cap comprises a rim (11) formed by afront wall (5), lateral walls (6, 8) joined toward the upper part bymeans of a nonplanar portion of the surface (12). The lower part of thetoe cap has a flange (13) which is joined to the shoe via the sole (7).The opposite end of the nonplanar surface (12) terminates in the rearwall (14) (see FIG. 6). This rim (11) recedes from the front wall (5)toward the rear wall (14), along the internal face of the toe cap, toterminate in the step (18) (FIG. 8) at a distance (x) of typically 0.8to 1.0 cm. FIGS. 8 and 10 are transverse and longitudinal section viewsshowing the step (18).

The rear wall (14) is a semicylindrical wall generally following theshape of a rounded tip, the rim which joins the lateral walls (6, 8),the rear wall (14) and the upper surface (12) is a rounded rim (FIG. 3).

The design of the toe cap of the present invention forms a frameworkwhich, owing to its disposition in space and the development of theangles, is extraordinarily rigid and resistant to impacts. Thanks to thedesign of the toe cap, the elements (4, 6, 8 and 11) and the flange (13)and its ends terminating in a point conduct the force of the impact overthe walls and to the sole, preventing the toes from being exposed to theimpact. In addition, the flange (13) prevents the penetrating action tothe contact surface of toe cap/sole, reducing the risk to the 5 toes ofthe user of the safety and protection footwear. It also preventsmovement of the toe cap at the moment of sustaining an impact or acompression with a force as defined in the aforementioned ranges (FIGS.3 and 5).

To calculate the shape of the toe cap of the present invention, one usesas the base the last of patent application No. MX/a/2007/003886, whoseproprietor is the same as the present application. This last, derivingfrom an anthropometric study, made possible the perfect adaptation tothe morphology of the worker wearing the safety and protection footwear.

Accordingly, the design of the protective toe cap bases the definitionof its dimensions on the last corresponding to the size of the footwear.It is not a universal toe cap in the sense of not changing itsdimensions with the footwear, but rather its dimensions are modified inaccordance with the size of the footwear to which it will be adapted,which is not the case with the toe caps of the prior art.

The variables that were considered for the development of the industrialfootwear last were in general, see FIG. 1B: “recio” (R), width of thefoot (AP), instep circumference (CE), heel width (T), instep length(LE), dimensions of the toes, fibular length of instep (LFEm), height of“recio” (AR) (Height of the circumference of the ball of the foot),instep height (AE), big toe angle (αg), little toe angle (αm), length offoot (LP), instep length (LE), length of foot at 16% (LP16), length offoot at 50% (LP50), a certain tolerance, metatarsal width and length,plantar length and width, tip height, heel width (AT), circumference ofthe toe area (CAD), heel bulb width, etc.

Additional considerations for the design of the last in the area of thetip that will define the design of the toe cap are: the anatomicaldistribution of the heads of the metatarsals, the inclusion of the 5toes, the displacement of the foot while walking, the foot flexure zone.The values obtained in the anthropometric study sample determined thedimensions applied specifically to the tip of the last so that thedesign of the toe cap will use the dimensions of same as its base.

It is important to note that a study on determining the ability of toecaps to cover or protect the toes found that the designs of the priorart do not protect the five toes, but only four of them, leavinguncovered the little toe, which is also the most fragile toe of thefoot. Hence the need to design a toe cap that covers this last toe.

During the research, some inconveniences were encountered, such as thefact that increasing the depth of the toe cap reduced the mobility ofthe foot, making the use very uncomfortable. Therefore, some additionalconsiderations were taken into account to dimension and design the toecap of the present invention. Other considerations for the calculationand design of the toe cap are: the thickness of the materials for sole(E7), the thickness of the lining (E5) to be used, thickness of the tab(not shown), as well as the dimensions of the last (1), as shown inFIGS. 2A, 2B, 3 and 8A.

An additional protective space has been added to the last along thelength and height in order to provide freedom of movement to the toesand create a grace space in the event of a compression or impactaccident to which the toes may be subjected, this consideration being 3to 7 mm in addition.

There are many other considerations for calculating the final dimensionsof the protective toe cap; even so, the most important part forachieving the objective of the present application is the form of thecontour of the rim (11) of the toe cap, to calculate which the followingwas taken into account:

1. The point of depth adequate to the flexure was obtained in additionto the mathematical model by subjecting the industrial shoe to thefunctions of walking and flexure.

2. The dimensions of the toes, which were determined by using thethree-dimensional scanning system known as INFOOT, translating the filesby means of an adapter known as LINE CONVERTER to a dimension evaluationsystem known as RHINOCEROS. The transformation of the information toRHINOCEROS made it possible to evaluate with precision thethree-dimensional dimensions of the toes and thus establish the designcriteria for the tip of the last and, consequently, those of the toecap.

The information obtained from the population evaluated by thethree-dimensional measurement system using INFOOT is subjected tostatistical analysis to determine the trends of the measurements andobtain the most representative ones for the population segments studied.

The development and use of a footwear constructed with the initialmockups of the toe cap and translucent materials making it transparentand the recommendations established in the various studies carried outwith regard to the design of the footwear established the criteria fordetermining the depth measurements of the toe cap or protective tip,such as carrying out various activities with the footwear that mightcause discomfort in the foot, such as squatting down to perform anactivity, and checking whether the depth of the toe cap is exceeded. Inthis case, the discomfort produced would be detected in the flexurezone.

3. The width of the one-piece toe cap is provided directly by themeasurements produced by the anthropometric study, in which it ispossible to establish the measurements of the toes and translate theminto the measurements of the last.

4. Starting with the electronic capture of the last by means of theauxiliary design software (known as RHINOCEROS), in which the images ofthe bodies of the previously designed lasts were captured, this systemenables detailed working on the design and measurements of parts andcomponents of interest. In this way, and given that the starting pointfor the design of the toe cap or protective tip is the last, one firstestablishes the basic measurements that will correspond to those of thetoe cap: width, height and depth.

Once the points on the last have been indicated and identified, a firstabstraction of the toe cap is performed, obtaining an image whichreplicates an exact image of the tip of the last with the dimensions ofthe desired depth. On the lines defined for the width, height and depthas defined on the last, one determines the additional advantagesrequired to integrate in the design the dimensions and thickness of thesole, tab, and lining.

By means of the electronic file that has been generated for each of thedesigns and sizes of the toe cap, one can properly establish theestablished dimensions, which are: interior mark, central mark, exteriormark, height mark and width mark, all these measurements being interiorto the toe cap.

5. The width of the toe cap is provided directly with the measurementsput out by the anthropometric study, from which it is possible toestablish the measurements of the toes in their entirety, in order totranslate to the last the location of the metatarsal heads of the fivetoes one locates the points (g) and (a) (see FIG. 2A), which are theinternal and external fibular lengths of the last; these points beingjoined together to determine the curved line A.

6. In order to cover in the best way the first (big toe) and fifth(little toe) digits of the foot, without interfering with its flexure, 4the points of digits 1 and 5 on the curve D-D′ are projected to theplantar base of the last with an angle of inclination adequate to coverthe mentioned digits without causing rubbing in them and to providegreater stability to the toe cap by means of this design, establishingin this way two points on the plantar base of the last that areidentified as P and C. The measurement of a straight line that joinspoints P and C will determine the width of the last for the toe cap (thewidth of the last determines the width of the toe cap), to thismeasurement will be added twice the thickness of the lining and twicethe thickness of the tab so that the insertion of the toe cap in theassembled footwear is correct.

Electronic Fitting of the Toe Cap Design to the Electronic Last

Once the adjustments have been made to the image originally abstractedfrom the last, one verifies that the adapted measurements properly fitthe electronic image of the assembled last. In this step, one canevaluate in detail whether the measurements of the designed toe capcoincide with those of the assembled last or, if not, performcorrections for the deviations found and repeat the evaluation, eventhough due to the precision of the software this is seldom feasible,since the electronic design systems in CAD environments have millimeterprecision, as is the case with RHINOCEROS.

It is possible to predict with good precision whether the adjustmentsapplied to the original dimensions of the toe cap will have a correctfit, since one can add to the original body of the last the thicknessdimensions of sole, tab and lining and electronically simulate whetherthe fit will be correct.

Given that the toe caps or protective tips are embodied in three typeswith respect to their supporting base, it is important to define in thedesign the type of base that is adequate for operational purposes of thepresent toe cap; the types of support base are:

1. no flange

2. half flange

3. complete flange.

The toe cap support base selected for the present invention is that witha complete flange (13).

One the final dimensions are in hand and the electronic file has beenevaluated, it is sent to a prototyping area where the details arechecked in order to:

1. Develop the electronic design program for the design in the numericalcontrol center (CNC).

2. Make adjustments to match up the dimensions of the electronic designof the toe cap with the dimensions of the electronic design of the mold.

3. Calculate the external dimensions required by the design of the toecap to comply with the specifications of the established standard.

4. Using a trial design, one determines the dimensional variables havinga high probability of complying with the results of the experimentaldesign and finally those of the reference standard.

5. One obtains the dimensionality and formulation, as well as all theprocessing conditions resulting in compliance with the specifications inorder to achieve industrial reproducibility of the toe cap.

6. With the certified toe caps, footwear is developed to evaluate twofundamental aspects:

-   -   a) Functionality of the design in use, by evaluating the freedom        of movements in different positions and activities of the user,        without the design in any way interfering with same.    -   b) Laboratory tests to evaluate the compliance in complete        footwear and define whether the toe cap or the construction        shape of the footwear need to be adjusted.

Determination of the Curvature D-D′ of the Rim (11):

To calculate the curvature of the rim (11), defined by the line D-D′(see FIG. 1A), the following procedure was followed:

1. One determines the actual length (10) of the last by placing thecentral part of the heel and tip on the sole of the last (1) and thecentral part of the tip of the last; once the points are located, onetakes a measurement, following the contours of the plantar shape of thelast; in this way, one obtains the value “L” of the last, as shown inFIG. 4.

2. One traces the line of the top central axis, locating the points ofthe line from the central part of the flat to the central point of thetip of the last.

3. One obtains a value L/6.416 and applies it in the body of the last,measuring from a perpendicular line, traced on edge from the tip of thelast and following along the line of the central axis, until theresultant value of L/6.416 is located. In addition, one must considerthe value T/3, which should be measured from a straight line parallel tothe internal fibular [line] which touches the flexure line point A untilit reaches the point defined by L/6.416, so that in this way using(L/6.416, T/3) as coordinates one determines the point P2 as one of thepoints dictating the curvature D-D′ (FIGS. 1A, 1B, 3 and 6).

Considering that:

a) For the fifth digit (little toe) (P4): it is only covered as far asthe zone of the nail, equivalent to a quarter of the length of thedigit, since to cover a greater zone would create a rubbing effectagainst the walls of the toe cap with the natural movement of the foot.

b) For the first digit (big toe) (P1): coverage is provided as far asthe flexure zone of the second metatarsal to avoid the aforementionedeffect.

Tracing a line between P1 , P2, P3, and P4, one defines the curvature ofthe toe cap that will effectively cover the five toes of the foot,respecting the flexure zone.

In keeping with the locations of the points P1 and P4, the followingformula was developed to calculate the curvature of the rim (11):

K=T/3+5 mm+10 mm, where:

K is a constant that defines the point coinciding with the central lineof the last (10) and with the central line of the curvature of the toecap. Mathematically, it is defined as the distance A-P3 (see FIG. 1A),which is equal to ⅓ of T+5 mm+10 mm.

T is the width of the heel.

P1 is defined as the point on the curve of the toe cap closest to theline of descent on the last on the lateral wall to the first digit (bigtoe).

P2 is defined as the maximum point of curvature most pronounced towardthe curvature of the last.

P3 is the distance at which the curvature of the toe cap coincides withthe central axis of the last.

P4 is the point closest to the line of descent to the zone of the 5thdigit (little toe) or external line of the last.

Having defined the elements contained in the formula for K, the formulasfor location of P1 to P4 for men will be as follows:

P1=K−(0 to 7 mm)

P2=K+(0 to 6 mm)

P3=K

P4=K−(1 to 2 mm),

and for women:

P1=K−(9 to 12 mm)

P2=K−(1 to 3 mm)

P3=K

P4=K+(2 to 7 mm).

For the remaining dimensions, an image editing program was used thatmade it possible to visualize more objectively the position on the lastof the 5 metatarsal heads, adjusting the points a-g as the points whichgive us the position “A” or initial flexure line, see FIG. 2A.

In the above image, one can observe the position of the metatarsal headsof the skeletal system of the foot (b, c, d, e and f), locating thepoints of the lines of internal fibular length LFI and external fibularlength (LFE), respectively correlating the points ((a) and (g)) andfinally joining these points to determine a form with specialcurvatures, defining the area of flexure on the last.

We now proceeded to determine the following dimensions:

Ia.—Dimensions of the Last in the Zone D-D′

Zone D is the curvature over the last of the toe cap and the height isto be considered at the highest point:

R=maximum height of the last in zone “D” (not considering the camber)

Z=maximum width of the last in the plantar base of the zone “D”

And considering:

Thickness of materials:

From FIG. 3 one finds the measurements

-   -   Thickness of sole (E7)    -   Thickness of lining (E5)    -   Thickness of the tab (E4)

Then the first dimensional determinations will be:

-   -   Width of the toe cap (E2)    -   Height of toe cap (E9)    -   Then:    -   (E2)=Z+2 (E5)+2 (E4) (not considering the camber of the last).    -   (E9)=R+(E7)+2 (E5)+2 (E4) (not considering the camber of the        last).

From FIG. 4 one finds how to locate the lower line of the region D-D′,it is a region which defines a curvature symmetrical to the curvature ofthe metatarsal heads of the toes, a point at which intersect the centralline of the last with the form of the curvature, designated as K or P3,two points known as P1 and P4 that define the points on the curve Dclosest to the lateral walls of the last in the zone of the first andfifth metatarsal, lines running toward the lower part on the edge of thesole known as P and C, the joining of these two points P and C by ajunction line determines the length of the last to calculate that of thetoe cap.

The next step is to determine the line of the axis of the last, forwhich one traces a point tangential to the heel of the last (TT) andalso traces a point tangential to the tip of the last (PT), a junctionline is drawn between TT and PT (FIG. 4), which determines the line ofthe axis of the last in combination with the line of width of the toecap one can determine the external (PE), central (PC) and internal (PI)depths (as shown in FIG. 4).

Next, this line PC is divided by 4 to obtain the points of reference formeasurement of the external depth of the last for the toe cap, thecentral depth of the last for the toe cap and the internal depth of thelast for the toe cap, said points being known as X1, X2 and X3, see FIG.4.

In a manner parallel to the axis of the last, one draws lines from X1,X2, X3 to the limit points of the tip of the last on the plantar baseY1, Y2 and Y3, forming in this way the lines which define the followingdepths of the last with respect to the toe cap:

External depth of the last, the distance measured on the last from X1 toY1

Central depth of the last, the distance measured on the last from X2 toY2

Internal depth of the last, the distance measured on the last from X3 toY3

Then:

PEH=External depth of the last.=X1−Y1

PCH=Central depth of the last.=X2−Y2

PIH=Internal depth of the last.=X3−Y3

Ib. The Depths of the Toe Cap Are Determined by the Following Formulas:

PEC=External depth of the toe cap with respect to its internal arch.

PCC=Central depth of the toe cap with respect to its internal arch.

PIC=Internal depth of the toe cap with respect to its internal arch.

Then:

PEC=PEH+E5

PCC=PCH+E5

PIC=PIH+E5

Ic. Determination of the Length of the Heel

One determines the tangential point of the outer shank of the last, oncethis point is determined one takes a flexible tape and runs a parallelline “T” and marks this line on the last, at the same time taking itslength; once the line “T” is drawn, this length is divided by 3, asshown in FIG. 4, in this way one obtains an auxiliary value T/3 fordetermining the lines of flexing of the toes.

Id. Determination of the Point A or Mouth Height

Once the inner and outer tangential points of the last are determined inthe zone of the tip, one passes a measuring tape around the body of thelast and determines the point “A” at the intersection of the centralaxis line (10), as shown in FIGS. 1A, 2B and 4.

Ie. Determination of the Ppoint B

Starting from point “A” and on the central axis line one adds the valueof T/3 to this new measurement, it is known as the point “B”, thisdetermination is based on the golden proportion criteria of themorphology of the foot (see FIGS. 2A, 2B and 4).

If. Determination of the Point C

Once point B is determined, 5 mm are added to the central axis line(10), FIGS. 1A and 4. The criterion of the 5 mm added has beendetermined as the result of the location of the flexure zone of thefoot, translated to the last. This determines the point C, where islocated the line of flexure of the toes, translated to the last (FIGS.2A and 2B).

Ig. Determination of the Point D

In the process of construction where the protective tip is used, oneuses the element known as a tab, which is a strip of synthetic materialconsisting of two parts, one being inserted inside the edge or mouth ofthe toe cap and having a small step of 1 mm thickness and a width of 10mm; toward the outer part of the strip it has a measurement of 10 mm andin total the tab strip has a width of 20 mm.

To determine the point D, it is important to measure this so-called tabelement at two specific points, namely, the interior flange (18) and theexterior flange or rim (11), in this case the tab being used has adimension of 8 to 10 mm (x).

Considering that the distance A-D is the zone of flexure of the toes,the distance to be added in the central axis line (10) after the point(C) is equal to the outer width, that is, the distance of (C) (all thoseof FIGS. 2A and 2B), to this is added 8 to 10 mm and it gives us thepoint P3 of the curve (D) (FIG. 1A).

Ih. Determination of Width and Height for the Design of the Toe Cap

We have already explained, starting from the last, the definition andposition of the form and position of the curve point “D”, now making alongitudinal cut from position “D” we obtain the following image FIG. 3.

Ii. Definition of Angles of the Toe Cap

FIG. 6 shows the angle α which defines the angle between the maximumheight point of the region “D” and the line of support of the flange,said angle corresponds to 20 degrees, this enables an additionalstability of the toe cap, giving it antiroll properties and greaterdispersion of forces in the impact and compression tests.

In FIG. 7 one observes the angle β, which is formed with respect to astraight line from the inside width points of the toe cap between theinside and outside point equivalent to 5 degrees as the resultant of thecoverage for the 1st and 5th digits, which provides a larger coveragefor the fifth digit.

1. A toe cap for safety and protection footwear for protection of thefive toes of the foot, in a single piece, such that the design of thetoe cap allows for the protection of the 5 toes and such that it forms arigid framework resistant to impacts in accordance with standardindustry safety standards comprising: a front wall; two lateral wallsjoined at the top by means of a non-planar top surface; said front walland two lateral walls ending at the bottom in an internally directionedflange; a rim that joins said two lateral walls and said top surfacesuch that said rim recedes toward said front wall and terminates in astep.
 2. A toe cap for protection of the five toes of the foot, in asingle piece, according to claim 1, wherein said rim and said flangehave their ends terminating together in a tip such that the force of animpact upon said top surface of said toe cap is conducted along said twolateral walls and said front wall to a sole preventing the toes of awearer from being exposed to the impact.
 3. A toe cap for protection ofthe five toes of the foot, in a single piece, according to claim 2,wherein said flange prevents a penetrating action on said top surface ofsaid toe cap and sole reducing the risk to the 5 toes of the wearer ofthe safety and protection footwear.
 4. A toe cap for protection of thefive toes of the foot, in a single piece, according to claim 3, suchthat said rim recedes toward said front wall and terminates in a step ata distance of 0.8 to 1.0 cm.
 5. A toe cap for protection of the fivetoes of the foot, in a single piece, according to claim 4, wherein saidrim which joins said lateral walls, said front wall, and said topsurface is a rounded rim.
 6. A toe cap for protection of the five toesof the foot, in a single piece, according to claim 5, wherein said frontwall is a semi-cylindrical wall generally following the shape of arounded tip.
 7. A toe cap for protection of the five toes of the foot,in a single piece, according to claim 6, such that the mathematicalformulas for the computation of measurements P1 to P4 are; for men;P1=K−(0 to 7 mm); P2=K+(0 to 6 mm); P3=K; P4=K−(1 to 2 mm); and forwomen; P1=K−(9 to 12 mm); P2=K−(1 to 3 mm): P3=K: P4=K+(2 to 7 mm);where K is a constant that defines a point coinciding with a centralline of a last and with a central line of the curvature of said toe capand is defined as the distance to P3 that is equal to ⅓ of T+5 mm +10 mmwherein; T is the width of a heel of said last; P1 is a point on a curveof said toe cap closest to a line of descent on the lateral wall to afirst digit (big toe) on said last; P2 is a maximum point of curvaturemost pronounced toward the curvature of said last. P3 is a distance atwhich the curvature of said toe cap coincides with a central axis ofsaid last; and, P4 is a point closest to a line of descent to a zone ofthe 5th digit (little toe) or external line of said last.
 8. A toe capfor protection of the five toes of the foot, in a single piece,according claim 7, wherein an adjustment is additionally made for thelocation of the metatarsal heads of the toes of a wearer identified asP1 to P4 by means of the following mathematical formulas; (E2)=Z+2(E5)+2 (E4) (not considering the camber of the last); (E9)=R+(E7)+2(E5)+2 (E4) (not considering the camber of the last); wherein. zone D isthe curvature of said last over said toe cap; R=maximum height of saidlast in zone D (not considering the camber); Z=maximum width of saidlast in the plantar base of the zone D; Thickness of said sole (E7) E1;Thickness of a lining (E5) E2; Thickness of a tab (E4) E3; Width of saidtoe cap (E2) AC; and, Height of said toe cap (E9) ALC.
 9. A toe cap forprotection of the five toes of the foot, in a single piece, according toclaim 8, such that in addition one determines the depths of said toe capby means of the mathematical formulas:, PEC=PEH+E5; PCC=PCH+E5;PIC=PIH+E5; wherein: PEC=External depth of said toe cap with respect toits internal arch:, PCC=Central depth of said toe cap with respect toits internal arch; and, PIC=Internal depth of said toe cap with respectto its internal arch.
 10. A toe cap for protection of the five toes ofthe foot, in a single piece, according to claim 9, wherein oneadditionally determines an angle α of said toe cap between the maximumheight point of said zone D and a line of support of said flange.
 11. Atoe cap for protection of the five toes of the foot, in a single piece,according to claim 10, wherein said angle α of said toe cap is 20degrees.
 12. A toe cap for protection of the five toes of the foot, in asingle piece, according to claim 11, wherein said angle α of said toecap enables a greater dispersion of forces.
 13. A toe cap for protectionof the five toes of the foot, in a single piece, according to claim 12,wherein one additionally determines the angle β of said toe cap that isdetermined with respect to a straight line from inside width points ofsaid toe cap between an inside and outside point.
 14. A toe cap forprotection of the five toes of the foot, in a single piece, according toclaim 13 wherein said angle β of said toe cap is 5 degrees.
 15. A toecap for protection of the five toes of the foot, in a single piece,according to claim 14, wherein said angle β of said toe cap provides agreater coverage of the fifth digit (little toe).
 16. (canceled)